Dr. Messersmith on Molecular Markers to be Aware of in CRC

Wells A. Messersmith, MD, co-director of the Developmental Therapeutics Program, and director, GI Cancer Program, at the University of Colorado School of Medicine, discusses molecular markers to be aware of in patients with colorectal cancer (CRC).

There are several molecular markers that should be tested for, including microsatellite stability (MSS) also known as mismatch repair proficiency, says Messersmith. In this case, physicians are looking for the editing function in DNA to ensure that patients don’t have an inherited defect which manifests as Lynch syndrome. Patients with Lynch syndrome are at an increased risk of developing certain tumors. As such, it is suggested that every patient with CRC be tested for this abnormality. If found, the entire family could be treated with appropriate measures, such as screening programs, explains Messersmith.

Polymerase chain reaction-based testing is typically recommended in the case of MSS, whereas immunohistochemistry is typically used to detect mismatch repair proficiencies; both tests are used to detect inherited or acquired mismatch repair. Whether inherited or acquired, patients with these abnormalities will typically receive immunotherapy. However, these patients only comprise approximately 3% to 15% of the overall patient population, concludes Messersmith.